Yellow azo dyestuff and process of preparing the same



Patented Sept. 1a, 1928.

UNITED STATES.

PATENT OFFICE..-

ERICH FISCHER AND CARL ERICK HELLER, OF HOCEST-ON-THE-MAIN, GERMANY,

ASSIGNORS '10 GRASSELLI DYESTUFF CORPORATION, OF NEW YORK, N. 'Y., A COR- PORA'IION OF DELAWARE.

YELLOW AZO DYESTUFF AND PROCESS OF PREPARING THE SAME.

No Drawing. Application filed April 20, 1927, Serial No. 185,356, and in Germany May 3, 1926.

Our present invention relates to the manufacture of a yellow azo dyestufl.

It is known that 'by far most of the yellow monoazodystufls hitherto used for dyeing 5 acetate silk, yield phototrope dyeings on the acetate silk. Such yellow phototrope dyestuffs, especially in mixtures with red and blue dyestuffs, temporarily lose their yellowish color after having been exposed a short 1 (tiimi to the light, but regain it by lying in the ar v Now we have found that the dyestufi' obtainable from diazotized para-nitraniline and 1-nitro-2.4-diaminobenzene has the property 1 of dyeing acetylcellulose a beautiful, nonphototrope, golden-yellow shade of excellent fastness properties.

The said properties of the new dyestufl are particularly remarkable in view ,of the fact that for instance the dyestufi' obtained by coupling diazotized meta-nitraniline with 1- nitro-2A-diaminobenzene yields only very weak dyein s on acetate silk. It is true that other comblnations with nitro-meta-phenylenediamine such as for example diazotized x NH:

OsN-O-N-N The dyestufi is particularly suitable for printin acetate silk.

We c aim:

1. The process of preparing a yellow azo m dyestuflf, particularly sultable for dyeing and printing acetate silk, which consists in coupling dia-zotized para-nitraniline with l-nitro- 2.4-diaminobenzene.

2. As a new product, the azo dyestufi which is substantially identical with the dyestuif produced by the hereindescribed process of coupling diazotized para-nitraniline with 1-nitro-2.4-diaminobenzene, being a yellow powder and dyeing acetate silk a beautiful, non-phototrope, golden-yellow shade of e xcellent properties as to fastness.

3. Acetate silk, d ed or rinted with the azo dyestufi referre to in c aim 2.

In testimony whereof, we aflix our signa- 75 tures.

- ERIOH'FISCHER.

CARL ERICH MULLER. 

